ci: fix re cmake build

.github/workflows/build.yml

@@ -37,10 +37,16 @@ jobs:
       if: ${{ runner.os == 'macOS' }}
       run: |
         echo "OPENSSL_ROOT_DIR=/usr/local/opt/openssl" >> $GITHUB_ENV
+
+    - name: make re/rem
+      shell: bash
+      run: |
+        cd ..
+        for p in re rem; do
+          cmake -S $p -B $p/build
+          cmake --build $p/build -j
+        done
 
     - name: retest
       run: |
-        cd ..
-        make -C re libre.a
-        cmake -S rem -B rem/build && cmake --build rem/build
-        cd retest && cmake . && make && ./retest -r
+        cd ../retest && make && ./retest -r